Mechanical locking system for floor panels

ABSTRACT

Floor panels with a flexible tongue in an insertion groove, the flexible tongue is designed to cooperate, in a connected state with a tongue groove of another panel, the panels are adapted to be locked together by vertical folding, the flexible tongue has a projection portion which, in a connected state projects outside the insertion groove and cooperates with the tongue groove, said projecting portion has a beveled and/or rounded sliding surface and the panels have a sliding surface adapted to cooperate therewith during vertical folding, the flexible tongue during the vertical folding is displaced twice in the horizontal direction, a first displacement is effected by the vertical folding of the fold panel whereby at least a part of the flexible tongue is bent, a second displacement of the flexible tongue towards its initial position is accomplished substantially by a spring effect caused by said bending of said flexible tongue.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/158,776, filed on Jun. 13, 2011, which is a continuation of U.S.application Ser. No. 12/868,137, filed on Aug. 25, 2010, now U.S. Pat.No. 7,980,041, which is a continuation of U.S. application Ser. No.11/822,681, filed on Jul. 9, 2007, now U.S. Pat. No. 7,802,411, which isa continuation of U.S. application Ser. No. 10/970,282, filed on Oct.22, 2004, now U.S. Pat. No. 7,454,857. This application claims thebenefit of U.S. application Ser. No. 13/158,776, U.S. application Ser.No. 12/868,137, U.S. application Ser. No. 11/822,681 and U.S.application Ser. No. 10/970,282. U.S. application Ser. No. 13/158,776,U.S. application Ser. No. 12/868,137, U.S. application Ser. No.11/822,681 and U.S. application Ser. No. 10/970,282 are herebyincorporated by reference in their entireties.

TECHNICAL FIELD

The invention generally relates to the field of mechanical lockingsystems for floor panels and such building panels that are made of aboard material. The invention relates to panels provided with suchlocking systems, elements for such locking systems and methods formaking and installing panels with such locking systems.

FIELD OF APPLICATION OF THE INVENTION

The present invention is particularly suitable for use in floatingfloors, which are formed of floor panels which are joined mechanicallywith a locking system integrated with the floor panel, i.e. mounted atthe factory, are made up of one or more upper layers of veneer,decorative laminate or decorative plastic material, an intermediate coreof wood-fibre-based material or plastic material and preferably a lowerbalancing layer on the rear side of the core. The following descriptionof prior-art technique, problems of known systems and objects andfeatures of the invention will therefore, as a non-restrictive example,be aimed above all at this field of application and in particularlaminate flooring formed as rectangular floor panels with long andshorts sides intended to be mechanically joined on both long and shortsides. The long and shorts sides are mainly used to simplify thedescription of the invention. The panels could be square, the sidescould have an angle other than 90 degree and they could have more than 4sides. It should be emphasized that the invention can be used in anyfloor panel and it could be combined with all types of known lockingsystem, where the floor panels are intended to be joined using amechanical locking system in the horizontal and vertical directions. Theinvention can thus also be applicable to, for instance, solid woodenfloors, parquet floors with a core of wood or wood-fibre-based materialand a surface of wood or wood veneer and the like, floors with a printedand preferably also varnished surface, floors with a surface layer ofplastic or cork, linoleum, rubber. Even floors with hard surfaces suchas stone, tile and similar are included and floorings with soft wearlayer, for instance needle felt glued to a board. The invention can alsobe used for joining building panels which preferably contain a boardmaterial for instance wall panels, ceilings, furniture components andsimilar.

BACKGROUND OF THE INVENTION

Laminate flooring usually consists of a core of a 6-12 mm fibre board, a0.2-0.8 mm thick upper decorative surface layer of laminate and a0.1-0.6 mm thick lower balancing layer of laminate, plastic, paper orlike material. The surface layer provides appearance and durability tothe floor panels. The core provides stability, and the balancing layerkeeps the panel plane when the relative humidity (RH) varies during theyear. The floor panels are laid floating, i.e. without gluing, on anexisting sub floor. Laminate flooring and also many other floorings aremade by the surface layer and the balancing layer being applied to acore material. This application may take place by gluing a previouslymanufactured decorative layer, for instance when the fibre board isprovided with a decorative high pressure laminate which is made in aseparate operation where a plurality of impregnated sheets of paper arecompressed under high pressure and at a high temperature. The currentlymost common method when making laminate flooring, however, is directlaminating which is based on a more modern principle where bothmanufacture of the decorative laminate layer and the bonding to thefibre board take place in one and the same manufacturing step.Impregnated sheets of paper are applied directly to the panel andpressed together under pressure and heat without any gluing.

Traditional hard floor panels in floating flooring of this type areusually joined by means of glued tongue-and-groove joints.

In addition to such traditional floors, which are joined by means ofglued tongue-and-groove joints, floor panels have recently beendeveloped which do not require the use of glue and instead are joinedmechanically by means of so-called mechanical locking systems. Thesesystems comprise locking means which lock the panels horizontally andvertically. The mechanical locking systems are usually formed bymachining of the core of the panel. Alternatively, parts of the lockingsystem can be formed of a separate material, for instance aluminium orHDF, which is integrated with the floor panel, i.e. joined with thefloor panel in connection with the manufacture thereof.

The main advantages of floating floors with mechanical locking systemsare that they can easily and quickly be laid by various combinations ofinward angling, snapping-in and insertion. They can also easily be takenup again and used once more at a different location. A further advantageof the mechanical locking systems is that the joint edges of the floorpanels can be made of materials, which need not to have good gluingproperties. The most common core material is fibreboard with highdensity and good stability usually called HDF—High Density Fibreboard.Sometimes also MDF—Medium Density Fibreboard—is used as core.

Definition of Some Terms

In the following text, the visible surface of the installed floor panelis called “front side”, while the opposite side of the floor panel,facing the sub floor, is called “rear side”. The edge between the frontand rear side is called “joint edge”. By “horizontal plane” is meant aplane which extends parallel to the outer part of the surface layer.Immediately juxtaposed upper parts of two adjacent joint edges of twojoined floor panels together define a “vertical plane” perpendicular tothe horizontal plane.

By “joint” or “locking system” are meant co acting connecting meanswhich connect the floor panels vertically and/or horizontally. By“mechanical locking system” is meant that joining can take place withoutglue. Mechanical locking systems can in many cases also be joined bygluing. By “integrated with” means formed in one piece with the panel orfactory connected to the panel.

By a “flexible tongue” is meant a separate tongue which has a lengthdirection along the joint edges and which is forming a part of thevertical locking system and could be displaced horizontally duringlocking. The tongue could be for example flexible and resilient in sucha way that it can bend along its length and spring back to its initialposition.

By “flexible tongue blank” are meant two or more flexible tongues whichare connected to a one piece component. Examples of such flexible tongueblanks will be described in more detail below.

By “fixing the flexible tongue” is meant that the flexible tongue shouldat least be sufficiently attached to the floor panel so as not toincidentally fall off during handling of the floor panel, at thefactory, during transport and/or in installation. By “mechanicallyfixed” is meant that the fixing is essentially due to shape or frictionforce.

By “angling” is meant a connection that occurs by a turning motion,during which an angular change occurs between two parts that are beingconnected, or disconnected. When angling relates to connection of twofloor panels, the angular motion takes place with the upper parts ofjoint edges at least partly being in contact with each other, during atleast part of the motion.

By “vertical folding” is meant a connection of three panels where afirst and second panel are in a connected state and where an anglingaction connects two perpendicular edges of a new panel to the first andsecond panel. Such a connection takes place for example when a long sideof first panel in a first row is already connected to a long side of asecond panel in a second row. The third panel is than connected byangling to the long side of the first panel in the first row. Thisspecific type of angling action, which also connects the short side ofthe new panel and second panel, is referred to as vertical folding

Prior-Art Technique and Problems Thereof

For mechanical joining of long sides as well as short sides in thevertical and horizontal direction (direction D1, D2) several methods areused but the locking is always performed in 3 steps where angling orsnapping are combined with displacement along the joint edge in thelocked position after an optional side has been joined.

-   -   Angling of long side, displacement and snapping-in of short side    -   Snapping-in of long side, displacement and snapping-in of short        side.    -   Angling of short side, displacement of the new panel along the        short side edge of the previous panel and finally downward        angling of two panels.

These laying methods can also be combined with insertion along the jointedge.

It is known the locking system may, however, be formed so thatsnapping-in may occur by a motion which is vertical to the surface ofthe floor panel. Generally the long side is locked by angling and theshort side with a vertical angling which locks with a snap action. Sucha system in described in WO 01/0248127 (Akzenta) The connection ofpanels is complicated and difficult since fibres must be compressed anda hammer with a tapping block must be used. The panels are locked invertical direction mainly by a friction force and the locking strengthis low.

It is known that floor panels may be locked on long and short sidevertically and horizontally with one simple vertical folding action (WO03/083234 Applicant Valinge Aluminium). This document comprises a partof this application. The object of WO 03/083234 is to provide a jointsystem and floor panels which can be laid with a vertical folding.

A floor panel with a vertical joint in the form of a flexible tongue anda groove is provided, the tongue being made of a separate material andbeing flexible so that at least one of the sides of the floor panel canbe joined by a vertical motion parallel to the vertical plane.

This document also show how a joint system can be made with a flexiblespring tongue which can be displaced and/or compressed horizontally inand out or alternatively be bent vertically up or down. It describes aseparate tongue of, for instance, wood fibre material, which can bedisplaced horizontally by means of a flexible material, for instance arubber paste. It also describes an embodiment with a tongue, which hasan inner part that is resilient.

This known technology with a tongue which during locking moveshorizontally in relation to the adjacent edges offers several advantagesover the known installation methods. The locking is easy and fastersince 3 steps are reduced to one step.

The invention described in WO 03/083234 does not however show the bestmethod to lock floor panels with a vertical folding. The production costand the locking function could be improved considerably.

BRIEF DESCRIPTION AND OBJECTS THEREOF

A first overall objective of the present invention is to provide alocking system based on a vertical folding with a flexible tongueconnected in a tongue groove. The locking system should make it possibleto lock all four sides of one panel vertically and horizontally to otherpanels with an angling action only. The costs and functions should befavorable compared to the known technology. An essential part of theoverall objective is to improve the function and costs of those parts ofthe locking system that causes the flexible tongue to displace duringlocking and spring back in locked position.

More specifically the object is to provide a vertical folding lockingsystem with a flexible tongue where one or several of the followingadvantages are obtained.

The flexible tongue should preferably be possible to displacement duringlocking with such a low force that no tools will be needed in connectionwith installation.

The spring effect should be reliable and the flexible tongue shouldalways move back to its pre-determined position when the panels havebeen brought to the position where they are to be locked.

The vertical locking should be strong and prevent that two locked panelswill move vertically when humidity is changing or when people walk on afloor.

The locking system should be able to lock floor panels vertically withhigh precision so that the surfaces are essentially in the same plane.

The vertical locking system should be designed in such a way that thematerial and production costs could be low.

The separate flexible tongue should be possible to connect to the floorpanel in a simple and cost effective way. The connection should keep theflexible tongue connected to the panel during production, transport andinstallation.

A second objective is to provide methods to produce the flexible tongueand flexible tongue blanks which are later to constitute parts of themechanical locking system of the floor panels.

A third object is to provide a rational method for joining the flexibletongues with the joint portion of the floor panel to form an integratedmechanical locking system where the flexible tongue is factory connectedto the floor panel.

A fourth object is to provide installation methods to connect floorpanels with vertical folding.

The above objects of the invention are achieved wholly or partly by alocking system, floor panels, a flexible tongue, a flexible tongue blankand production and installation methods according to the independentclaims. Embodiments of the invention are evident from the dependentclaims and from the description and drawings.

Although it is an advantage to integrate the flexible tongue with thepanel in the factory before installation, the invention does not excludean embodiment in which flexible tongues are delivered as separatecomponents to be connected to the panel by the installer prior toinstallation.

According to a first aspect of the invention, a new floor panelcomprising connecting means which are integrated with the floor paneland adapted to connect the new floor panel with an essentially identicalfirst and second floor panel is provided.

The upper joint edges of said new and second floor panels define in theconnected state a vertical plane.

The connecting means are designed to connect said new floor panel withsaid second floor panel in a horizontal direction perpendicular to saidvertical plane and in a vertical direction parallel to the verticalplane. The vertical connection comprising a flexible tongue in a slidinggroove in one of the new or second floor panels. The sliding groove isformed in the edge of the panel and is open towards the vertical plane.The flexible tongue has a length direction along the joint edges, awidth in the horizontal plane perpendicular to the length and athickness in the vertical direction.

The flexible tongue is designed to cooperate, in said connected statewith a tongue groove of another one of the new or second floor panels.

The horizontal connection comprising a locking strip which projects fromsaid vertical plane and carries a locking element 8 in the second panel.

The locking strip 6 is designed to cooperate, in said connected state,with a downward open locking groove of the new floor panel. The newfloor panel could be locked to the first and second floor panel withvertical folding. The flexible tongue is during the vertical foldingdisplaced two times in the sliding groove. The first displacement iseffected by the vertical folding of the new floor panel whereby at leasta part of the flexible tongue is bent in the length direction andparallel with the width.

A second displacement of the flexible tongue towards its initialposition is accomplished substantially by a spring effect caused by saidbending of said flexible tongue.

According to a first aspect of the second objective a tongue blank isprovided consisting of several flexible tongues connected to each other.This facilitated automatic handling of the tongues in connection withthe fixing of the flexible tongues into the displacement groove.

According to a first aspect of the third objective a production methodis provided to fix the flexible tongue in the displacement groove. Theflexible tongue is separated from a tongue blank and displacedessentially parallel to its width or length into the displacement groovewhere it is fixed with a friction force.

According to a first aspect of the fourth objective installation methodsare provided which make it possible to connect floor panels verticallyand horizontally long side to short side with a simple angling motion.

The invention allows horizontal and vertical locking of all sides offloor panels with a simple angling of the long sides only. Therefore itis especially suited for use in floor panels which are difficult todisplace in locked position for example because they are long, in panelswhere parts of the locking system is made of a material with highfriction, such as wood and in locking systems which are produced withtight fit, without play or even with pretension. Especially panels withsuch pretension where the locking strip is bent in locked position andpresses the panels together are very difficult to displace. A lockingsystem that allows a vertical folding according to the invention willdecrease the installation time of such panels considerably.

The invention is also especially well suited for panels which areconnected long side to short side and for panels which are wide forexample with a width larger than 20 cm. Such panels are difficult tosnap on short side and in most materials they must have a verticallocking to avoid height differences between the joint surfaces.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 a-d illustrate one embodiment of a locking system according tothe invention.

FIGS. 2 a-eillustrate in different steps mechanical joining of a floorpanels according to an embodiment of the invention.

FIGS. 3 a-b show floor panels with a mechanical locking system on ashort side.

FIGS. 4 a-b show the flexible tongue during the locking action.

FIGS. 5 a-b show how short sides of two floor panels could be lockedwith vertical folding.

FIGS. 6 a-c show another embodiment of the invention.

FIGS. 7 a-f show different embodiments of a flexible tongue.

FIGS. 8 a-8 d show schematically how a separate flexible tongue could beconnected to a floor panel.

FIGS. 9 a-f show schematically different embodiments according to theinvention.

FIGS. 10 a-d show how two types of panels could be locked vertically andhorizontally long side to short side with a simple angling action only.

FIGS. 11 a-d show another embodiment according to the principles in FIG.10 a-d.

FIGS. 12 a-f show square panels and alternative locking methods.

FIGS. 13 a-c show how widely used traditional panels could be adjustedto vertical folding.

FIG. 14 shows the flexible tongue in another embodiment according to theinvention.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

A first preferred embodiment of a floor panel 1, 1′ provided with amechanical locking system according to the invention is now describedwith reference to FIGS. 1 a-1 d. To facilitate understanding, thelocking systems in all figures are shown schematically. It should beemphasized that improved or different functions can be achieved usingcombinations of the preferred embodiments. The inventor has tested allknown and especially all commercially used locking systems on the marketin all type of floor panels, especially laminate and wood floorings andthe conclusion is that at least all these known locking systems whichhave one or more tongues could be adjusted to a system with one ore moreflexible tongues according to the invention. Most of them could easilybe adjusted in such a way that they will be compatible with the presentsystems. Several flexible tongues could be located in both adjacentedges, one over the other and they could be on different levels in thesame edge or installed in the same groove after each other. The flexibletongue could be on long and/or short sides and one side with a flexibletongue could be combined with another side which could have all knownlocking systems, preferably locking systems which could be locked byangling or a vertical movement. The invention does not exclude floorpanels with flexible tongues on for example a long and a short side.Such panels could be installed by a vertical motion without any angling.Angles, dimensions, rounded parts etc are only examples and could beadjusted within the principles of the invention.

A first preferred embodiment of a floor panel 1, 1′ provided with amechanical locking system according to the invention is now describedwith reference to FIGS. 1 a-1 d.

FIG. 1 a illustrates schematically a cross-section of a joint between ashort side joint edge 4 a of a panel 1 and an opposite short side jointedge 4 b of a second panel 1′.

The front sides 61 of the panels are essentially positioned in a commonhorizontal plane HP, and the upper parts 21, 41 of the joint edges 4 a,4 b abut against each other in a vertical plane VP. The mechanicallocking system provides locking of the panels relative to each other inthe vertical direction D1 as well as the horizontal direction D2.

To provide joining of the two joint edges in the D1 and D2 directions,the edges of the floor panel have in a manner known per se a lockingstrip 6 with a locking element 8 in one joint edge, hereafter referredto as the “strip panel” which cooperates with a locking groove 14 in theother joint edge, hereafter referred to as the “fold panel”, andprovides the horizontal locking.

The mechanical locking system according to the invention comprises aseparate flexible tongue 30 connected into a displacement groove 40formed in one of the joint edges. The flexible tongue 30 has a grooveportion P1 which is located in the displacement groove 40 and aprojecting portion P2 projecting outside the displacement groove 40. Theprojecting portion P2 of the flexible tongue 30 in one of the jointedges cooperates with a tongue groove formed in the other joint edge.

In this embodiment, the panel 1 could for example have a body or core 60of wood-fibre-based material such as HDF, plywood or solid wood.

The flexible tongue 30 has a protruding part P2 with a rounded outerpart 31 and a sliding surface 32 which in this embodiment if formed likea bevel. It has upper 33 and lower 35 tongue displacement surfaces andan inner part 34.

The displacement groove 40 has an upper 42 and lower 46 opening which inthis embodiment are rounded, a bottom 44 and upper 43 and lower 45groove displacement surfaces which preferably are essentially parallelwith the horizontal plane HP.

The tongue groove 20 has a tongue locking surface 22 which cooperateswith the flexible tongue 30 and locks the joint edges in a verticaldirection D1. The fold panel 1′ has a vertical locking surface 24, whichis closer to the rear side 62 than the tongue groove 20. The verticallocking surface 24 cooperates with the strip 6 and locks the joint edgesin another vertical direction. The fold panel has in this embodiment asliding surface 23 which cooperated during locking with the slidingsurface 32 of the tongue.

FIGS. 2 a -2 e shows how a fold panel 1′ could be locked to a strippanel 1. The figures show a vertical motion of two panels towards eachother. The figures also shows a part of a vertical folding connectingthree panels to each other as shown in FIG. 5 a. The FIGS. 2 a-2 e showshow the two cross sections A-A and A′-A′ of FIG. 5 a will be connectedwhen the fold panel 1′ will be angled towards the strip panel 1. FIG. 2b-c show how the sliding surfaces cooperate when the folding panel 1′ ismoved vertically towards the strip panel 1. The flexible tongue 30 isdisplaced with a first displacement essentially horizontally in thedisplacement groove 40 towards the bottom 44. When the panels are in theposition where they are to be locked to each other, the flexible tongue30 springs back with a second displacement towards its initial positionand the panels are locked vertically between the vertical lockingsurface 24 and the strip 6 and the lower displacement surface 35 and thetongue locking surface 22.

The flexible tongue 30 should preferably be connected to thedisplacement groove 40 with high precision. Depending on thecompressibility and friction between the flexible tongue 30 and thedisplacement groove 40, the tongue as whole or different parts could beconnected with a small play, for example 0.01-0.10 mm, a precise fit ora pre tension. Wax or other friction reducing materials or chemicalscould be applied between the flexible tongue and the displacement grooveand/or in the tongue groove and/or in the locking system in order tofacilitate displacement of the tongue and the locking and/or tofacilitate the connection of the flexible tongue in the displacementgroove.

Even with a play, a precise fit between the upper joint edges could beaccomplished. The lower tongue displacement surface 35 could be formedto press the tongue locking surface 22 and the vertical locking surface24 towards the strip 6. For example the protruding part P2 of the tonguedisplacement surface 35 could be formed with a small angle to thehorizontal plane HP. The protruding part P2 of the flexible tongue willtilt towards the front side 61 and a part of the upper tonguedisplacement surface 33 will press against the upper groove displacementsurface 43 while parts of lower displacement surfaces 35,45 close to thebottom 44 of the displacement groove 40 will press against each other.In such an embodiment, the vertical fit between the upper joint edgeswill mainly depend on the production tolerances between the verticallocking surfaces 24 and a vertical contact surface 6′, in thisembodiment located on the upper part of the strip 6, which in lockedposition will be in contact with each other and preferably press againsteach other. The flexible tongue 30 could be formed to cause a permanentpressure force horizontally in the locked position. This means that theflexible tongue 30 will only partly spring back to the initial position.The flexible tongue 30 could optionally be designed with such dimensionsthat in locked position it will move slightly towards its initialposition when people walk on the floor or when the panels at warping indifferent humidity. Gradually a perfect vertical connection will beaccomplished.

FIG. 3 a shows a cross section A-A of a panel according to FIG. 3 b seenfrom above. The flexible tongue 30 has a length L along the joint edge,a width W parallel to the horizontal plane and perpendicular to thelength L and a thickness T in the vertical direction D1. The sum of thelargest groove portion P1 and the largest protruding part P2 is thetotal width TW. The flexible tongue has also in this embodiment a middlesection MS and two edge sections ES adjacent to the middle section. Thesize of the protruding part P2 and the groove portion P1 varies in thisembodiment along the length L and the tongue is spaced from the twocorner sections 9 a and 9 b. This shape is favorable in order tofacilitate the first and the second displacement of the flexible tongue30.

FIGS. 4 a and 4 b shows the position of the flexible tongue 30 after thefirst displacement towards the bottom 44 of the displacement groove 40.The displacement is caused essentially by bending of parts of theflexible tongue 30 in its length direction L parallel to the width W.This feature is essential for this embodiment of the invention andoffers several advantages

A first important advantage is that the tongue could be made of ratherrigid material which is strong and stabile in the vertical directionwhile at the same time a flexibility in horizontal direction D2 could beaccomplished. The bending portions are could be made considerably largerthan the horizontal displacement needed to accomplish the locking.

A second advantage is that the parts which are flexible and facilitatesthe first and second horizontal displacement also supports the verticalstability of the tongue. The advantage is that the total width TW of theflexible tongue and the depth of the displacement groove could be ratherlimited. This improves the strength and moisture deformation of thejoint edge. As a non restrictive example it could be mentioned that thetotal width TW of the flexible tongue could be about 5-15 mm

A third advantage is that the flexible tongue could be made in one pieceof a single material without any soft and compressible materials. Thiswill decrease the production cost and facilitate the connection of thetongue in the displacement groove.

The sliding grove is in this preferred embodiment a continuous grooveover the whole length of the join edge. The displacement groove (40)could however be formed in only a part of the edge and it does not haveto be parallel with the edge. The displacement groove (40) could forinstance be curved. Such a groove is easy to produce with a rotatingtool which could move against the edge.

The fold panel could be disconnected with a needle shaped tool whichcould be inserted from the corner section 9 b into the tongue grove 20and press the flexible tongue back into the displacement groove 40. Thefold panel could than be angled up while the strip panel is still on thesub floor. Of course the panels could also be disconnected in thetraditional way.

FIGS. 5 a and 5 b shows one embodiment of a vertical folding. A firstpanel 1″ in a first row is connected to a second 1 panel in a secondrow. The new panel 1′ is connected with its long side 5 a to the longside 5 b of the first panel with angling. This angling action alsoconnects the short side 4 b of the new pane with the short side 4 a ofthe second panel. The fold panel 1′ is locked to the strip panel 1 witha combined vertical and turning motion along the vertical plane VP. Theprotruding part P2 has a rounded and or angled folding part P2′ whichduring folding cooperates with the sliding surface 23 of the foldingpanel 1′. The combined effect of a folding part P2′, and a slidingsurface 32 of the tongue which during the folding cooperates with thesliding surface 23 of the fold panel 1′ facilitates considerably thefirst displacement of the flexible tongue 30. The horizontal pressingforce could be spread over a much larger portion than the thickness T ofthe flexible tongue and the fold panel could easily be folded down witha low force even if the spring effect of the bending is high. As a nonrestrictive example it could be mentioned that a vertical pressing forceof 10 N against a piece, which has a length of 100 mm along the longside, applied on the long side 5 b of the fold panel, as shown in FIG. 5a, could displace a projecting portion P2 to the inner position even ifthe spring force is 20 N. Most of the pressure force will be horizontaland the flexible tongue will be displaced into the displacement groove40 without any risk of a block effect caused by friction or a tiltingand/or vertically bending of the flexible tongue 30. It is an advantageif the locking system is designed in such a way that the locking element8 is partly in the locking groove 14 when the first displacement starts.This is shown in FIG. 5 b. The top edges 41,21 are partly in contactwith each other and the fold panel 1′ is in the correct startingposition. The locking element 8 and the locking groove 14 prevent thestrip panel 1 and the fold panel 1′ to separate when the flexible tongue30 is pressed into the displacement groove 40. En essential feature ofthis embodiment is the position of the projecting portion P2 which isspaced from the corner section 9 a and 9 b. The spacing should bepreferably at least 10% of the length of the joint edge, in this casethe visible short side 4 a. FIG. 5 a shows that the spacing from theboth corner section 9 a and 9 b gives the flexibility that the foldpanel could during the vertical folding be connected to the long side ofthe first panel 1″ with the tongue side 5 a or the strip side 5 b

FIGS. 6 a-6 b show that the flexible tongue could be in the edge of thefold panel 1′. The sliding surface 32 of the tongue cooperates in thisembodiment with the top edge of the strip panel. Thanks to the foldingpart P2′, the locking could be made without any risk of damaging the topsurface layer at the edge. The advantage of this embodiment is that ashort side with a flexible tongue could be connected to a traditionallong side or short side locking system with a strip 6 and a tonguegroove 20 in the same edge.

FIG. 6 c shows an embodiment where the displacement groove 40 is notparallel with the horizontal plane HP. This facilitates the connectionof the flexible tongue 30 into the displacement groove 40. Theprotruding part of the flexible tongue 30 is wedge shaped in order topress the vertical contact surface 6′ and the vertical locking surface24 against each other. The locking surfaces between the locking element8 and the locking groove 14 are angled and have an angle which is lessthan 90 degree against the horizontal plane HP and the locking systemcould be connected with a tight fit and/or pre tension.

FIGS. 7 a-7 e shows different embodiments of the flexible tongue 30. InFIG. 7 a the flexible tongue 30 has on one of the edge sections afriction connection 36 which could be shaped for instance as a localsmall vertical protrusion. This friction connection keeps the flexibletongue in the displacement groove 40 during installation, or duringproduction, packaging and transport, if the flexible tongue isintegrated with the floor panel at the factory. FIG. 4 b show that thefriction connection 36 keeps one edge section ES connected while theother edge section ES' moves along the edge. The length L′ in the innerposition is in this embodiment larger than the length L in lockedposition.

FIG. 7 b shows a tongue blank 50 consisting of several flexible tongues30 connected to each other. In this embodiment the flexible tongue 30 ismade with moulding preferably injection moulding. Any type of polymermaterials could be used such as PA (nylon), POM, PC, PP, PET or PE orsimilar having the properties described above in the differentembodiments. These plastic materials could be reinforced with forinstance glass fibre. A preferred material is glass fibre reinforced PA.

FIGS. 7 c-eshow different embodiments made by injection moulding. Withthis production method a wide variety of complex three-dimensionalshapes could be produced at low cost and the flexible tongues 30 couldeasily be connected to each other to form tongue blanks 50. Of coursethe flexible tongue 30 could be made from metal. FIG. 7 e shows that theflexible tongue could be made of an extruded or machined plastic sectionwhich could be further shaped with for example punching to form aflexible tongue according to the invention. Materials such as plastic,metals preferably aluminium, wood based sheet material such as HDF andcompact laminate could be used.

FIG. 7 f shows an embodiment which consist of two sections 38 and 39which are connected to each other. This will be explained more inconnection to FIGS. 12 d-f.

In general any shape which allows that a part of the tongue could bendin length direction and spring back in such a way that the projectingportion could be displaced with 0.1 mm or more, will be possible to use.Normally the displacement should be 1-3 mm but very small displacementsof some 0.1 mm could be enough to form a vertical locking which preventsvertical movement especially in HDF material.

FIGS. 8 a-8 d show schematically a production method to fix the flexibletongue to the displacement groove. In this embodiment the flexibletongue is mechanically fixed. Of course glue or mechanical devices canalso be used. To simplify the understanding the panel 1′ is located withits front side up. The panel could also be turned with the rear side up.The tongue blanks 50 are moved trough a separation unit 51 whichseparates the flexible tongue 30 from the tongue blank 50. The flexibletongue 30 could than be moved to a lower level with a vertical device55. This motion could also be combined with the separation. A pusher 54moves the flexible tongue 30 into the displacement groove 40 andconnects it with the friction connection 36. The flexible tongue isguided over the strip 6 between an upper 52 and lower 53 guidingdevices. Vacuum could also be used to connect the flexible tongue 30 tothe upper 52 guiding device during the horizontal displacement into thedisplacement groove 40. A lot of alternatives are possible within themain principles that the flexible tongue is separated from a tongueblank containing at least two connected flexible tongues and displacedessentially parallel to its width and/or length into the displacementgroove 40 where it is fixed with a friction force.

FIGS. 9 a to 9 f are examples which show that all known locking systemscould be adjusted to vertical folding with a flexible tongue 30according to the invention and that the flexible tongue 30 could beattached optionally to the strip or fold panel. In the embodiment ofFIG. 9 e, the strip 6 is not rigid enough to form a vertical contactsurface. This could be solved by a tongue 10 and a groove 9 above theflexible tongue 30. Of course the vertical contact surface 6′ could be apart of the tongue groove and the vertical locking surface 24 could bethe projecting portion of the tongue as shown in FIG. 9 e.

FIG. 10 a-b shows how a locking system could be designed to lock longside 4 a to long side 4 b with angling, short side 5 a to short side 5 bby vertical folding and/or angling and short side to long side withvertical folding or angling. FIGS. 10 c-10 d show how two panels A and Bwith mirror inverted locking systems could be locked to a floor with anadvanced installation pattern. Panels 1-6 could be installed withangling. Panel 7 could be installed by angling the short side to thelong side of pane 6. Panels 8-9 could be installed by angling. Panel 12is installed by angling the short side. Panels 13-23 are installed byfolding. Panels 24-26 are installed by angling and panels 27-34 byfolding. Thanks to the flexible tongue 30 on the short side the wholefloor could be installed with a simple angling action in spite of thefact that all panels are connected on all sides vertically andhorizontally and all panels are connected long to long side and long toshort side. This installation method could be used in connection withall types of flexible tongues and not only those embodiments that bendalong the length direction. FIG. 10 b show that the locking system couldbe locked with a pressure force F caused by the flexible tongue 30.

FIGS. 11 a-11 d show how A and B panels with a flexible tongue could beinstalled and locked vertically D1 and horizontally D2 in a single ordouble herringbone pattern with only a simple angling action.

FIG. 12 a-c shows vertical folding installation with square panels. Theflexible tongue 30 has several protruding parts P2. This embodimentcould be used as an alternative to several separate flexible tongueswhen the length of the joint edge exceeds for example 200 mm. Thefriction connection 36 could be located for example in a middle section.

FIG. 12 d-eshows an alternative way to displace the flexible tongue. Themethod could be combined with a flexible tongue according to FIG. 7 f.The new panel 1′ is in angled position with an upper part of the jointedge in contact with the first panel 1″ in the first row. The firstpanel 1′, the fold panel, is than displaced towards the second panel 1until the edges are essentially in contact and a part of the flexibletongue 30 is pressed into the displacement groove 40 as can be seen inthe FIG. 12 e. The new panel 1′ is than folded down towards the secondpanel 1. FIG. 12 f show that the tongue could be on the folding panel.Since the displacement of the new panel 1′ presses an edge section ofthe flexible tongue 30 into the displacement groove 40, vertical foldingwill be possible to make with less resistance. Such an installationcould be made with a flexible tongue that has a straight protrudingpart. The flexible tongue 30 does not have to bend in the lengthdirection if it has a flexible device such as rubber that could becompressed. The bending could be replaced by a horizontal turning actionwhere one edge section of the flexible tongue during locking is closerto the bottom 44 of the displacement groove 40 than another oppositeedge section.

FIGS. 13 a-c shows how a known locking system, used in large volumes onthe marked, could be converted to a vertical folding, preferably in twosteps. The first step is to replace the traditional tongue 10 with aflexible tongue 30. In this embodiment the locking systems will becompatible which means that an old and new panel could be locked to eachother. After a while when all products in the shops are sold, the groove9 of the strip part could be adjusted.

Within the invention a lot of alternatives are possible to accomplishvertical folding with a flexible tongue.

A flexible tongue could be produced according to the same principle asknown mechanical devices which create a spring effect similar to lockingdevices used in doors, windows, furniture, cars and mobile phones. Theflexible tongue with these mechanical devices could be formed withdimensions suitable for 6-15 mm floorings, especially wood floorings,and inserted into the edge. FIG. 13 d shows that the flexible tongue(30) could for example be mounted in a separate sliding section 56 madeof plastic or metal or any other suitable material and containing acompressible or flexible rubber, metal or plastic component (57) orsimilar able to create the spring effect. This sliding section 56 couldbe connected into the edge of the floor panel in a holding groove 40′which in this embodiment is rounded and has a shape similar to a part ofa rotating saw blade. Since the holding groove 40′ only is formed in apart of the short side edge, it could be made rather deep and the edgewill still have sufficient strength. A preferable feature of thisembodiment is that the deepest part of the holding groove 40′ is onlylocated in a part of the edge. Contrary to the other embodiments theholding groove 40′ is not parallel with the joint edge and does notcover the whole edge. Of course other shapes are possible and theparallel groove is not excluded.

Especially on long and wide floor panels rather complicated devicescould be used since only 2-4 pieces are required per m2 of flooring.Even with a rather high unit price, the advantages with vertical foldingare considerable and could overcome a rather high cost for the lockingsystem. Due to the fact that the short sides are not sawn very often,metal components could also be used and these components could be formedin such a way that they are easy to remove from the floor panel if theshort side edge must be sawn.

In floor panels with a width of about 20 cm a flexible tongue with alength of a few cm is enough if it is positioned in the middle part ofthe short side about 6-9 cm from the corner section.

The flexible tongue could also be made of one single component asdescribed in the embodiment above and with a thickness of about 1 mmonly and could be used to connect floorboards with a thickness down to 4mm.

All features of the embodiment described above could be combined witheach other or used separately. The flexible tongues could be combinedwith all shown displacement or holding grooves. The locking systemscould be used in any shown joint or floor panel. The system according toFIG. 14 could for example be used in floor panels described in FIGS. 10a-d. The tongue as shown in FIG. 7 f could also have a shape as shown IFIG. 7 b and it could be made to bend in the length direction where thisbending is partly supported by a flexible material 38. The lockingstrips could in all embodiments be made of a separate material or in onepiece. Part of the strip 6 in FIG. 14 could be removed under the plasticcomponent 56 to facilitate fixing to the joint.

The method to produce a separate tongue which is inserted into a groovecould of course be used to save material and improve friction propertieseven if the tongue is not flexible or displaceable. The methods andprinciple could also be used together with a flexible tongue that couldbe bent in vertical direction up and/or down during locking.

The system could be used to connect tile shaped panes installed on awall. The tile could be connected to each other and to a locking memberfixed to the wall.

Although only preferred embodiments are specifically illustrated anddescribed herein, it will be appreciated that many modifications andvariations of the present invention are possible in light of the aboveteachings and within the purview of the appended claims withoutdeparting from the spirit and intended scope of the invention.

1. A building panel having an edge portion presenting a sidewardly opengroove, in which a tongue formed as a separate part is received, whereinthe tongue, which is of an elongated shape, is intended to lock into atongue groove of an adjacent building panel, wherein the tongue whenreceived in the sidewardly open groove is bendable in a planesubstantially parallel with a main plane of the panel, such that a partof the tongue is resiliently displaceable in said plane, wherein thepart of the tongue is displaceable in the range of 0.1-3.0 mm duringlocking.
 2. The building panel claimed in claim 1, wherein the part ofthe tongue is displaceable in the range of 0.1-1.0 mm during locking. 3.The building panel as claimed in claim 1, wherein the edge portioncomprises a strip extending horizontally below and beyond the sidewardlyopen groove.
 4. The building panel as claimed in claim 3, wherein thestrip carries a locking element, and wherein said strip is designed tocooperate, in a connected state, with a downward open locking grooveformed in the adjacent building panel.
 5. The building panel as claimedin claim 4, wherein the sidewardly open groove is spaced verticallyupwards from the upper part of the locking element.
 6. The buildingpanel as claimed in claim 1, wherein the edge portion of the buildingpanel comprises a core comprising HDF material.
 7. The building panel asclaimed in claim 1, wherein the tongue is fixed into the groove withglue.
 8. The building panel as claimed in claim 1, wherein the tongue isfixed into the groove with a friction connection.
 9. The building panelas claimed in claim 7, wherein the friction connection comprises aprotrusion arranged at the upper surface and/or at the lower surface ofthe tongue.
 10. The building panel as claimed in claim 1, wherein thetongue is asymmetrical in the longitudinal direction.
 11. The buildingpanel as claimed in claim 1, wherein the tongue has a length directionalong an edge portion, a width in main horizontal plane of the panelperpendicular to the length and a thickness in the vertical directionperpendicular to the main horizontal plane and wherein the width islarger than the thickness.
 12. The building panel as claimed in claim 1,wherein the tongue has a groove portion which is located in thesidewardly open groove and a projection portion which, in an unlockedposition and in a connected state, projects outside the sidewardly opengroove.
 13. The building panel as claimed in claim 1, wherein theflexible tongue is made of moulded polymer material and reinforced withfibres.
 14. The building panel as claimed in claim 1, wherein thebuilding panel is a floor panel.
 15. The building panel as claimed inclaim 1, wherein the tongue comprises a V or U-shaped section.